EP1089537A2 - Line circuit apparatus for supplying power to a telephone set in telecommunication systems - Google Patents

Line circuit apparatus for supplying power to a telephone set in telecommunication systems Download PDF

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Publication number
EP1089537A2
EP1089537A2 EP00402138A EP00402138A EP1089537A2 EP 1089537 A2 EP1089537 A2 EP 1089537A2 EP 00402138 A EP00402138 A EP 00402138A EP 00402138 A EP00402138 A EP 00402138A EP 1089537 A2 EP1089537 A2 EP 1089537A2
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EP
European Patent Office
Prior art keywords
voltage
source
telecommunications device
power
hook
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP00402138A
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German (de)
French (fr)
Other versions
EP1089537A3 (en
Inventor
Douglas Youngblood
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Intersil Corp
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Intersil Corp
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Filing date
Publication date
Application filed by Intersil Corp filed Critical Intersil Corp
Publication of EP1089537A2 publication Critical patent/EP1089537A2/en
Publication of EP1089537A3 publication Critical patent/EP1089537A3/en
Withdrawn legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations
    • H04M19/005—Feeding arrangements without the use of line transformers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems

Definitions

  • This invention relates to a subscriber loop interface circuit ("SLIC") and more specifically to a SLIC with a single power source and a voltage regulator.
  • SLIC subscriber loop interface circuit
  • the SLIC provides on-hook signals such as a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook while maintaining industry standard voltage limits across the terminals of the telecommunications device during all modes of operation.
  • a SLIC is employed in a subscriber loop as an interface between a subscriber network and a subscriber telecommunications device, such as a residential telephone, telephone answering machine, modem, or similar device.
  • a subscriber loop includes a SLIC, a subscriber telecommunications device, and a pair of subscriber lines for connecting the SLIC to the subscriber telecommunications device.
  • the subscriber lines, subscriber terminal device, and SLIC together may form a continuous circuit for establishing two-way communications between the SLIC and the subscriber telecommunications device.
  • a SLIC supplies different voltages to a telecommunications device depending on whether the telecommunications device is on-hook/off-hook, or if the telecommunications device is to ring, e . g .,to notify the telecommunications device of the presence of an incoming call.
  • Well known industry standards set maximum limits for voltages appearing across the terminals of a telecommunications device for on-hook/off-hook conditions (approximately - 56V), and ringing conditions (approximately -120V RMS ).
  • Prior art non-ringing SLICs for traditional POTS systems are designed to meet the above requirements by using two separate voltage sources, V BAT and V RING , that power separate circuits for on-hook/off-hook condition and for ringing conditions, as illustrated in Figures 1 and 2.
  • V BAT supplies power during on-hook/off-hook conditions
  • V RING supplies power during ringing conditions.
  • a switch is used to alternately connect V BAT or V RING to the telecommunications device.
  • FIG 1 illustrates a typical subscriber loop of a POTS system including a non-ringing SLIC 100 which contains the on-hook/off-hook circuits.
  • the power supply 104 (“V BAT1 ”) supplies power to the non-ringing SLIC 100.
  • the power supply 105 (“V RING1 ”) supplies power to the ring generator 101 which provides the ringing signal to the subscriber phone 106.
  • the switch 103 alternately connects the subscriber phone 106 to the non-ringing SLIC 100, so as to supply power to the subscriber phone 106 from V BAT , and the ring generator 101, so as to supply power to the subscriber phone 106 from V RING , in response to a signal from the ring command generator 102.
  • V BAT typically supplies power to the non-ringing SLIC 100 at a voltage less than the industry standard maximum voltage of approximately -56V (“V MAX ”) across the terminals of the subscriber phone 106 ("V TERM ").
  • Figure 2 illustrates known subscriber loop of a POTS system whose operation is essentially similar to the device in Figure 1. Like components are given similar numbers in Figures 1 and 2.
  • Prior art ringing SLICs use two power supplies as well as complex control and selection circuits, as illustrated in Figure 3, or a single programmable power supply, as illustrated in Figure 4, to ensure that the correct voltage is applied to the on-hook/off-hook circuits as well as the ringing circuits without exceeding the industry standard maximum voltage limits for the on-hook/off-hook condition.
  • both of these solutions are undesirable because they substantially increase the cost and complexity of the ringing SLIC.
  • FIG. 3 illustrates a typical subscriber loop including a ringing SLIC 210 which contains both the on-hook/off-hook circuits 203 and the ringing circuits 204.
  • the power supply 207 (“V BAT2 ”) and the power supply 208 (“V RING2 ”) supply power to the ringing SLIC 210.
  • a ringing SLIC of this type requires the addition of the control circuits 201 and the voltage select circuits 200 in order to apply the proper voltage to the subscriber phone 206 for the different operating conditions of the subscriber phone 206 without allowing V TERM to exceed V MAX .
  • Figure 4 illustrates another known ringing SLIC 210 where the voltage select circuits 200 and V BAT2 and V RING2 are replaced by a programmable power supply 209. Like components are given similar numbers in Figures 3 and 4.
  • the present invention includes a power supply for a telecommunications device comprising a source of power, first and second speech amplifiers, first and second switches, a voltage regulator characterized in that control circuit responsive to one or more external control signals for either (a) operatively connecting said source of power to said speech amplifiers while operatively disconnecting said source of power from said switches and said voltage regulator or (b) operatively connecting said source of power to said switches and said voltage regulator while operatively disconnecting said source of power to said speech amplifiers.
  • a ringing SLIC of the present invention avoids the problems of the prior art by using a single power source in conjunction with a voltage regulator, as illustrated in Figure 5.
  • the single power supply supplies sufficient voltage to provide a ringing signal to the telecommunications device during ringing conditions.
  • the voltage regulator limits the voltage across the terminals of the telecommunications device to a predetermined value below the industry standard voltage limits during on-hook/off-hook conditions.
  • the SLIC selectively enables or disables the speech amplifiers responsive to an external control signal that is independent of the on-hook/off-hook status of the telecommunications device.
  • the SLIC provides on-hook signals such as a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook.
  • the invention also includes an apparatus for supplying power to a telecommunications device comprising a source of power, first speech amplifier operatively connected to a control circuit, the negative terminal of said telecommunications device, said source of power, and ground, second speech amplifier operatively connected to said control circuit, the positive terminal of said telecommunications device, said source of power, and ground, characterized in that first switch operatively connected to said control circuit, the negative terminal of said telecommunications device, and a voltage regulator, second switch operatively connected to said control circuit, the positive terminal of said telecommunications device, and ground, said voltage regulator operatively connected to said control circuit, said source of power, and said first switch, and said control circuit responsive to one or more external control signals for selectively enabling said first and second speech amplifiers while disabling said first and second switches and said voltage regulator, and for selectively disabling said first and second speech amplifiers while enabling said first and second switches and said voltage regulator.
  • An object of the present invention is to obviate the problems in the prior art and to provide a novel SLIC and method in a subscriber loop, and which requires only one power supply.
  • Another object is to provide a novel SLIC and method with a voltage regulator for maintaining the voltage across the telecommunications device below the industry standard maximum voltage during all modes of operation, and to enable the speech amplifiers in response to an external control signal that is not a function of the off-hook status of the telecommunications device.
  • a further object is to provide a novel SLIC and method for selectively enabling the speech amplifiers to provide a ringing signal and/or a caller identification signal while the telecommunications device is on-hook
  • the SLIC 10 is connected to a telecommunications device 26 through subscriber lines 24.
  • the power supply 20 supplies a voltage, V SUPPLY , to the speech amplifiers 12a and 12b and the voltage regulator 16.
  • V SUPPLY is typically approximately -100V.
  • V TERM When the telecommunications device 26 is on-hook in a non-ringing condition, the voltage across the terminals of the telecommunications device 26 ("V TERM ”) is desirably below the industry standard maximum voltage of approximately -56V ("V MAX ").
  • V MAX the industry standard maximum voltage of approximately -56V
  • V TERM is maintained below V MAX in one of two ways. In the first method, V TERM is maintained below V MAX by using the speech amplifiers.
  • the control circuit 18, in response to a control signal 22, enables the speech amplifiers 12a and 12b while disabling the switches 14a and 14b and the voltage regulator 16. In this configuration, V TERM is maintained below V MAX by the well-known method of setting the speech amplifiers 12a and 12b to a predetermined output value, such as -50V.
  • the second, and novel, method uses the switches 14a and 14b and the voltage regulator 16 to maintain V TERM below V MAX .
  • the voltage regulator 16 is set to limit the voltage to the switch 14a to a predetermined value, V REF , where V REF is less than V MAX , thus maintaining V TERM below V MAX .
  • V REF is preferentially set less than V MAX . Therefore, for V SUPPLY less than or equal to V REF , V TERM is approximately equal to V SUPPLY . For V SUPPLY greater than V REF , V TERM is approximately equal to V REF .
  • the typical configuration for the SLIC 10, as described above, is that the speech amplifiers 12a and 12b are disabled and the switches 14a and 14b and the voltage regulator 16 are enabled.
  • the ringing signal is then transmitted to the telecommunications device 26 through the speech signal amplifiers 12a and 12b.
  • a data signal such as a caller identification signal
  • the configuration of the SLIC 10 changes.
  • the control circuit 18, in response to control signal 22, enables the speech amplifiers 12a and 12b while disabling the switches 14a and 14b and the voltage regulator 16.
  • V TERM is maintained below V MAX by the well-known method of setting the speech amplifiers 12a and 12b to a predetermined output value, such as -50V.
  • a subscriber line interface circuit for a telecommunications device powered from a single power source and using a voltage regulator to limit the voltage across the terminals of the telecommunications device to a predetermined value below the industry standard voltage limits.
  • the SLIC selectively enables or disables the speech amplifiers responsive to an external control signal that is independent of the on-hook/off-hook status of the telecommunications device.
  • the SLIC provides a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Interface Circuits In Exchanges (AREA)

Abstract

A subscriber line interface circuit ("SLIC") (10) for a telecommunications device powered from a single power source (20) and using a voltage regulator (16) to limit the voltage across the terminals of the telecommunications device to a predetermined value below the industry standard voltage limits. The SLIC (10) selectively enables or disables the speech amplifiers (120, 126) responsive to an external control signal (22) that is independent of the on-hook / off-hook status of the telecommunications device. The SLIC (10) provides a ringing signal and / or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook.

Description

This invention relates to a subscriber loop interface circuit ("SLIC") and more specifically to a SLIC with a single power source and a voltage regulator. The SLIC provides on-hook signals such as a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook while maintaining industry standard voltage limits across the terminals of the telecommunications device during all modes of operation.
A SLIC is employed in a subscriber loop as an interface between a subscriber network and a subscriber telecommunications device, such as a residential telephone, telephone answering machine, modem, or similar device. A subscriber loop includes a SLIC, a subscriber telecommunications device, and a pair of subscriber lines for connecting the SLIC to the subscriber telecommunications device. When a subscriber telecommunications device is in an off-hook condition, the subscriber lines, subscriber terminal device, and SLIC together may form a continuous circuit for establishing two-way communications between the SLIC and the subscriber telecommunications device.
A SLIC supplies different voltages to a telecommunications device depending on whether the telecommunications device is on-hook/off-hook, or if the telecommunications device is to ring, e.g.,to notify the telecommunications device of the presence of an incoming call. Well known industry standards set maximum limits for voltages appearing across the terminals of a telecommunications device for on-hook/off-hook conditions (approximately - 56V), and ringing conditions (approximately -120VRMS).
Prior art non-ringing SLICs for traditional POTS systems are designed to meet the above requirements by using two separate voltage sources, VBAT and VRING, that power separate circuits for on-hook/off-hook condition and for ringing conditions, as illustrated in Figures 1 and 2. Typically, VBAT supplies power during on-hook/off-hook conditions and VRING supplies power during ringing conditions. A switch is used to alternately connect VBAT or VRING to the telecommunications device.
Figure 1 illustrates a typical subscriber loop of a POTS system including a non-ringing SLIC 100 which contains the on-hook/off-hook circuits. The power supply 104 ("VBAT1") supplies power to the non-ringing SLIC 100. The power supply 105 ("VRING1") supplies power to the ring generator 101 which provides the ringing signal to the subscriber phone 106. The switch 103 alternately connects the subscriber phone 106 to the non-ringing SLIC 100, so as to supply power to the subscriber phone 106 from VBAT, and the ring generator 101, so as to supply power to the subscriber phone 106 from VRING, in response to a signal from the ring command generator 102.
VBAT typically supplies power to the non-ringing SLIC 100 at a voltage less than the industry standard maximum voltage of approximately -56V ("VMAX") across the terminals of the subscriber phone 106 ("VTERM").
Figure 2 illustrates known subscriber loop of a POTS system whose operation is essentially similar to the device in Figure 1. Like components are given similar numbers in Figures 1 and 2.
Prior art ringing SLICs use two power supplies as well as complex control and selection circuits, as illustrated in Figure 3, or a single programmable power supply, as illustrated in Figure 4, to ensure that the correct voltage is applied to the on-hook/off-hook circuits as well as the ringing circuits without exceeding the industry standard maximum voltage limits for the on-hook/off-hook condition. However, both of these solutions are undesirable because they substantially increase the cost and complexity of the ringing SLIC.
Figure 3 illustrates a typical subscriber loop including a ringing SLIC 210 which contains both the on-hook/off-hook circuits 203 and the ringing circuits 204. The power supply 207 ("VBAT2") and the power supply 208 ("VRING2") supply power to the ringing SLIC 210. A ringing SLIC of this type requires the addition of the control circuits 201 and the voltage select circuits 200 in order to apply the proper voltage to the subscriber phone 206 for the different operating conditions of the subscriber phone 206 without allowing VTERM to exceed VMAX.
Figure 4 illustrates another known ringing SLIC 210 where the voltage select circuits 200 and VBAT2 and VRING2 are replaced by a programmable power supply 209. Like components are given similar numbers in Figures 3 and 4.
The present invention includes a power supply for a telecommunications device comprising a source of power, first and second speech amplifiers, first and second switches, a voltage regulator characterized in that control circuit responsive to one or more external control signals for either (a) operatively connecting said source of power to said speech amplifiers while operatively disconnecting said source of power from said switches and said voltage regulator or (b) operatively connecting said source of power to said switches and said voltage regulator while operatively disconnecting said source of power to said speech amplifiers.
Conveniently, a ringing SLIC of the present invention avoids the problems of the prior art by using a single power source in conjunction with a voltage regulator, as illustrated in Figure 5. The single power supply supplies sufficient voltage to provide a ringing signal to the telecommunications device during ringing conditions. The voltage regulator limits the voltage across the terminals of the telecommunications device to a predetermined value below the industry standard voltage limits during on-hook/off-hook conditions. The SLIC selectively enables or disables the speech amplifiers responsive to an external control signal that is independent of the on-hook/off-hook status of the telecommunications device. The SLIC provides on-hook signals such as a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook.
The invention also includes an apparatus for supplying power to a telecommunications device comprising a source of power, first speech amplifier operatively connected to a control circuit, the negative terminal of said telecommunications device, said source of power, and ground, second speech amplifier operatively connected to said control circuit, the positive terminal of said telecommunications device, said source of power, and ground, characterized in that first switch operatively connected to said control circuit, the negative terminal of said telecommunications device, and a voltage regulator, second switch operatively connected to said control circuit, the positive terminal of said telecommunications device, and ground, said voltage regulator operatively connected to said control circuit, said source of power, and said first switch, and said control circuit responsive to one or more external control signals for selectively enabling said first and second speech amplifiers while disabling said first and second switches and said voltage regulator, and for selectively disabling said first and second speech amplifiers while enabling said first and second switches and said voltage regulator.
An object of the present invention is to obviate the problems in the prior art and to provide a novel SLIC and method in a subscriber loop, and which requires only one power supply.
Another object is to provide a novel SLIC and method with a voltage regulator for maintaining the voltage across the telecommunications device below the industry standard maximum voltage during all modes of operation, and to enable the speech amplifiers in response to an external control signal that is not a function of the off-hook status of the telecommunications device.
A further object is to provide a novel SLIC and method for selectively enabling the speech amplifiers to provide a ringing signal and/or a caller identification signal while the telecommunications device is on-hook
The present invention will now be described, by way of example, with reference to the accompanying drawings in which:
  • Figure 1 is a schematic circuit diagram of a traditional POTS prior art subscriber loop system with non-ringing SLICs.
  • Figure 2 is a schematic circuit diagram of a traditional POTS prior art subscriber loop system with non-ringing SLICs.
  • Figure 3 is a schematic circuit diagram of a prior art subscriber loop system with a ringing SLIC and control and voltage selection circuits.
  • Figure 4 is a schematic circuit diagram of a prior art subscriber loop system with a ringing SLIC and a programmable power supply.
  • Figure 5 is a schematic circuit diagram of a subscriber loop system including one embodiment of the present invention.
    • With reference to Figure 5, in a preferred embodiment of the SLIC 10 is connected to a telecommunications device 26 through subscriber lines 24. The power supply 20 supplies a voltage, VSUPPLY, to the speech amplifiers 12a and 12b and the voltage regulator 16. VSUPPLY is typically approximately -100V. The control circuit 18, in response to one or more external control signals 22, selectively enables the speech amplifiers 12a and 12b and disables the switches 14a and 14b and the voltage regulator 16 or selectively disables the speech amplifiers 12a and 12b and enables the switches 14a and 14b and the voltage regulator 16, as will be explained below.
    When the telecommunications device 26 is on-hook in a non-ringing condition, the voltage across the terminals of the telecommunications device 26 ("VTERM") is desirably below the industry standard maximum voltage of approximately -56V ("VMAX"). VTERM is maintained below VMAX in one of two ways. In the first method, VTERM is maintained below VMAX by using the speech amplifiers. The control circuit 18, in response to a control signal 22, enables the speech amplifiers 12a and 12b while disabling the switches 14a and 14b and the voltage regulator 16. In this configuration, VTERM is maintained below VMAX by the well-known method of setting the speech amplifiers 12a and 12b to a predetermined output value, such as -50V.
    The second, and novel, method uses the switches 14a and 14b and the voltage regulator 16 to maintain VTERM below VMAX. The control circuit 18, in response to a control signal 22, disables the speech amplifiers 12a and 12b while enabling the switches 14a and 14b and the voltage regulator 16. In this configuration, the voltage regulator 16 is set to limit the voltage to the switch 14a to a predetermined value, VREF, where VREF is less than VMAX, thus maintaining VTERM below VMAX.
    VREF is preferentially set less than VMAX. Therefore, for VSUPPLY less than or equal to VREF, VTERM is approximately equal to VSUPPLY. For VSUPPLY greater than VREF, VTERM is approximately equal to VREF.
    When the telecommunications device 26 is on-hook, the typical configuration for the SLIC 10, as described above, is that the speech amplifiers 12a and 12b are disabled and the switches 14a and 14b and the voltage regulator 16 are enabled. In this configuration, when a ringing or other typical on-hook signal is to be sent to the telecommunications device 26, the control circuit 18, in response to control signal 22 that is independent of the off-hook status of the telecommunications device 26, disables the switches 14a and 14b and the voltage regulator 16 while enabling the speech amplifiers 12a and 12b. The ringing signal is then transmitted to the telecommunications device 26 through the speech signal amplifiers 12a and 12b. The above procedure also applies if a data signal, such as a caller identification signal, is to be sent to the telecommunications device 26 while the telecommunications device is on-hook.
    When the telecommunications device 26 is on-hook and the SLIC 10 is in the above-described typical on-hook configuration and the telecommunications device changes status from on-hook to off-hook, the configuration of the SLIC 10 changes. The control circuit 18, in response to control signal 22, enables the speech amplifiers 12a and 12b while disabling the switches 14a and 14b and the voltage regulator 16. In this configuration, VTERM is maintained below VMAX by the well-known method of setting the speech amplifiers 12a and 12b to a predetermined output value, such as -50V.
    A subscriber line interface circuit ("SLIC") for a telecommunications device powered from a single power source and using a voltage regulator to limit the voltage across the terminals of the telecommunications device to a predetermined value below the industry standard voltage limits. The SLIC selectively enables or disables the speech amplifiers responsive to an external control signal that is independent of the on-hook/off-hook status of the telecommunications device. The SLIC provides a ringing signal and/or a caller identification signal through the speech amplifiers to the telecommunications device while the telecommunications device is on-hook

    Claims (10)

    1. A power supply for a telecommunications device comprising a source of power, first and second speech amplifiers, first and second switches, a voltage regulator characterized in that control circuit responsive to one or more external control signals for either (a) operatively connecting said source of power to said speech amplifiers while operatively disconnecting said source of power from said switches and said voltage regulator or (b) operatively connecting said source of power to said switches and said voltage regulator while operatively disconnecting said source of power to said speech amplifiers.
    2. A power supply as claimed in claim 1 characterized in that said voltage regulator provides an output voltage equal to the voltage of said source when the voltage of said source is below a predetermined voltage and said predetermined voltage when the voltage of said source is above said predetermined voltage.
    3. A power supply as claimed in claim 2 characterized in that wherein said control signals are not a function of the off-hook status of the telecommunications device, and in which said speech amplifiers may be selectively enabled to provide at least one of a ringing signal and a caller identification signal while the telecommunications device is on-hook.
    4. An apparatus for supplying power to a telecommunications device comprising a source of power, first speech amplifier operatively connected to a control circuit, the negative terminal of said telecommunications device, said source of power, and ground, second speech amplifier operatively connected to said control circuit, the positive terminal of said telecommunications device, said source of power, and ground, characterized in that first switch operatively connected to said control circuit, the negative terminal of said telecommunications device, and a voltage regulator, second switch operatively connected to said control circuit, the positive terminal of said telecommunications device, and ground, said voltage regulator operatively connected to said control circuit, said source of power, and said first switch, and said control circuit responsive to one or more external control signals for selectively enabling said first and second speech amplifiers while disabling said first and second switches and said voltage regulator, and for selectively disabling said first and second speech amplifiers while enabling said first and second switches and said voltage regulator.
    5. An apparatus as claimed in claim 4 characterized in that said voltage regulator provides an output voltage equal to the voltage of said source when the voltage of said source is below a predetermined voltage and said predetermined voltage when the voltage of said source is above said predetermined voltage.
    6. An apparatus including the power supply as claimed in claim 4 characterized in that said control signals are not a function of the off-hook status of the telecommunications device.
    7. An apparatus as claimed in claim 4 characterized in that said speech amplifiers may be selectively enabled to provide at least one of a ringing signal and a caller identification signal while the telecommunications device is on-hook.
    8. A method for supplying power to a telecommunications device comprising providing a source of power providing first and second speech amplifiers, providing first and second switches, providing a voltage regulator, characterized in that providing a control circuit responsive to one or more external control signals for either (a) operatively connecting said source of power to said speech amplifiers while operatively disconnecting said source of power from said switches and said voltage regulator or (b) operatively connecting said source of power to said switches and said voltage regulator while operatively disconnecting said source of power to said speech amplifiers.
    9. A method as claimed in claim 8 characterized in that said voltage regulator provides an output voltage equal to the voltage of said source when the voltage of said source is below a predetermined voltage and said predetermined voltage when the voltage of said source is above said predetermined voltage, and in which said control signals are not a function of the off-hook status of the telecommunications device.
    10. A method as claimed in claim 9 characterized by said speech amplifiers may be selectively enabled to provide at least one of a ringing signal and a caller identification signal while the telecommunications device is on-hook.
    EP00402138A 1999-07-30 2000-07-26 Line circuit apparatus for supplying power to a telephone set in telecommunication systems Withdrawn EP1089537A3 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    US365238 1999-07-30
    US09/365,238 US6137189A (en) 1999-07-30 1999-07-30 Line circuit apparatus for supplying power to a telephone set in telecommunication systems

    Publications (2)

    Publication Number Publication Date
    EP1089537A2 true EP1089537A2 (en) 2001-04-04
    EP1089537A3 EP1089537A3 (en) 2003-08-13

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    EP00402138A Withdrawn EP1089537A3 (en) 1999-07-30 2000-07-26 Line circuit apparatus for supplying power to a telephone set in telecommunication systems

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    US (1) US6137189A (en)
    EP (1) EP1089537A3 (en)
    JP (1) JP2001069537A (en)
    KR (1) KR20010015475A (en)

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    US6862352B1 (en) * 2000-10-11 2005-03-01 Intersil Corporation Controlled switching mechanism for accomplishing soft polarity reversal, ring-trip filtering, and line voltage measurements in a subscriber line interface circuit using common capacitor
    US6813340B1 (en) * 2000-11-28 2004-11-02 Cisco Technology, Inc. Ringing SLIC fault handling
    CA2360117A1 (en) * 2001-10-24 2003-04-24 Catena Networks Canada Inc. The application of pots ringing signals without interfering with dsl signals
    JP2003158590A (en) * 2001-11-22 2003-05-30 Fujitsu Ltd Subscriber line interface
    US7433464B2 (en) * 2004-10-15 2008-10-07 Universcel Corporation Communications systems and methods using wireline adapters
    US7925005B2 (en) * 2006-10-23 2011-04-12 Silicon Laboratories, Inc. Longitudinal balance calibration for a subscriber line interface circuit
    US20100080381A1 (en) * 2008-09-30 2010-04-01 Tesu Ion C Method and Apparatus for Supplying DC Feed to a Subscriber Line
    US20100080380A1 (en) * 2008-09-30 2010-04-01 Yan Zhou Method and Apparatus for Supplying DC Feed to a Subscriber Line

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    US4310733A (en) * 1979-05-28 1982-01-12 U.S. Philips Corporation Arrangement for applying signals to a telephone line
    EP0615375A2 (en) * 1993-03-12 1994-09-14 Advanced Micro Devices, Inc. Subscriber line interface circuit
    US5737411A (en) * 1994-12-29 1998-04-07 Advanced Micro Devices Inc. Battery switching in a telephone subscriber line interface circuit

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    US5247566A (en) * 1990-03-15 1993-09-21 Aisin Seiki Kabushiki Kaisha Apparatus for the transmission and reception of data

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    US4310733A (en) * 1979-05-28 1982-01-12 U.S. Philips Corporation Arrangement for applying signals to a telephone line
    EP0615375A2 (en) * 1993-03-12 1994-09-14 Advanced Micro Devices, Inc. Subscriber line interface circuit
    US5737411A (en) * 1994-12-29 1998-04-07 Advanced Micro Devices Inc. Battery switching in a telephone subscriber line interface circuit

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    Publication number Publication date
    KR20010015475A (en) 2001-02-26
    JP2001069537A (en) 2001-03-16
    EP1089537A3 (en) 2003-08-13
    US6137189A (en) 2000-10-24

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